3.1 BIOLOGICAL MOLECULES

joins two molecules by forming a bond while removing a h20

breaks a bond between two molecules by using a h20

glucose fructose galactose

glucose + glucose = maltose
glucose + galactose = lactose
glucose + fructose = sucrose

two OH top

two H top

one H and one OH

beta-1,4-glycosidic bond

long straight chains of beta glucose, running parallel to other chains allowing hydrogen bonds to form and these are then grouped into micro fibrils then macro fibrils giving lots of strength and rigidity

Made up of alpha glucose for starch, chains may be branched or not and the unbranched are wound into tight coils. Glycogen is similar but has shorter chains and is more branched

For storage:
cant cross cell membrane as its too big
insoluble so doesn't affect water potential
compact
For respiration:
Has branches so more ends for hydrolysing enzymes

Reducing sugars

1) add 2cm^3 of food sample to a test tube
2)Add same volume of benedict reagent to it
3)Gently warm it up via water bath
- If reducing should show a traffic light colour

1)Do benedict test giving negative result
2)Add another 2cm^3 of food sample to 2cm^3 of dilute HCL acid
3) Gently warm it up via water bath for 5 mins
4) Add sodium hydrogen carbonate solution to neutralise it
5)Add 2cm^3 of benedict and warm it up

1) Add drops of food sample to a spotting tile
2)Add drops of iodine solution
- if theres starch a blue black colour should appear

A hydrocarbon chain and a carboxyl group

They form an ester bond via condensation reactions.

saturated fatty acids which means they have no double bond in hydrocarbon chain and unsaturated fatty acids which means they have one or more double bonds in hydrocarbon chain.

Made up of unsaturated fatty acids which contain bends which causes the molecules to be further away from each other weakening the INFS so form liquids.

Saturated so they can be packed closer together donc form stronger INFS so solid

large
non polar
insoluble in water
Low mass to energy ratio
High carbon & hydrogen : oxygen ratio

Heat and electrical insulation
Energy and water source
Storage molecules

They are made up of a phosphate which is polar and a glycerol and two fatty acids which are non polar. Insoluble in water

Forms the cell surface membranes and separates the inside and outside of the cell
Control movement of molecules
Enable cell recognition as they can form glycolipids

1) Add 2cm^3 of food sample to test tube
2) Add 5cm^3 of ethanol and thoroughly shake it
3) Add 5cm^3 of water and gently shake it
If positive it should become a milky white colour

amine group H2N
carboxyl group COOH
variable side group R
hydrogen and a centre carbon

Bond between amino acids made by condensation reactions

The sequence of amino acids in a polypeptide chain

Hydrogen bonds form between oxygens and hydrogens in the peptide bond causing the chain to start folding and form alpha helices or beta pleated sheet

Further folding occurs to make it 3D and is held by hydrogen, ionic and disulphide bonds by side groups

2 or more polypeptide chains join together and can contain non protein parts called prosthetic groups

1) Add some of the food sample and add same volume of sodium hydroxide solution in test tube
2) Add few drops of dilute copper sulphate solution and mix gently
If protein a lilac or purple colour appears

Globular
Fibrous

Primary structure
pH

The temperature at which the enzyme works at its best and is maximum temperature before denaturing.

A molecule similiar in shape to a substrate allowing it to bind to active site, preventing a substrate from binding.
Reduces amt of E-S complexes but leaves after some time so can be overcome by increasing substrate concentration

A molecule which binds to an enzyme via an allosteric site and changes its tertiary structure so no substrate cant fit.
No E-S complex so can not be overcome by increasing substrate concentration

Pentose sugar
Phosphate group
nitrogen-containing base

DNA has deoxyribose with one less oxygen than RNA ribose

The hydroxyl group in pentose forms a phosphodiester bond with the phosphate group of another nucleotide. This is a condensation reaction

Its a polymer made up of nucleotides
2 polynucleotides strands are held together by hydrogen bonds forming a double helix
The two strands run antiparallel to each other

RNA is found in cytoplasm compared to DNA in nucleus
RNA is a much shorter molecule than DNA
RNA is one strand while DNA is two

1) DNA helicase breaks the hydrogen bonds between the strands and these become separated
2) Strands now act as templates as free nucleotides starts to complementarily bind to them
3) DNA polymerase then joins up these free nucleotides by phosphodiester bonds through a condensation reaction

IT means that new DNA molecule consists of one original strand and one newly replicated strand